Abstract: A new upgrading method of pyrolysis-oil was proposed to improve the quality of pyrolysis-oil to be an engine fuel. First, the raw pyrolysis-oil was treated by the combination of ether extraction and chemical catalysis. Secondly, the upgrading pyrolysis-oil/diesel blends were prepared by the ultrasonic treatment. The value of S, which is defined as the volume of upgrading pyrolysis-oil dissolved in a unit volume of diesel, was used for evaluating the emulsification of the blends. The results show that the amount of emulsifier plays an important part in the value of S. When the volume ratio of upgrading pyrolysis-oil, diesel and emulsifier equals 10:30:5, the optimal experimental condition is that the ultrasonic time is 20 min, the ultrasonic power is 540 W, the temperature is 50℃. By analyzing the physical characteristics, the blends are found to be stable and have a good combustion performance, which can be a promising alternative to diesel.